[Leetcode] 179. Largest Number @python

题目

Given a list of non negative integers, arrange them such that they form the largest number.

For example, given [3, 30, 34, 5, 9], the largest formed number is 9534330.

Note: The result may be very large, so you need to return a string instead of an integer.

题目要求

给定一个数组，要求对数组进行重新排列，使得连接起来形成的数字最大。

解题思路

对数组进行排序，比较函数(a,b)，比较（a + b)和（b＋a）的大小。
同时要注意数组元素都为0的情况

代码

class Solution(object):
    def largestNumber(self, nums):
        """
        :type nums: List[int]
        :rtype: str
        """
        def compare(a,b):
            return int(b + a) - int(a + b)
        nums = sorted([str(x) for x in nums],cmp = compare)
        ans = ''.join(nums).lstrip('0')

        return ans or '0'